1. Field of the Invention
The present invention relates to an inductance-type rotation angle sensor including a rotor attached to a rotating body to be detected and a stator attached to an irrotational control housing, the stator formed by printing an annularly formed magnetic conductor and a receiving conductor placed adjacent to the magnetic conductor on a glass-epoxy-resin substrate, the rotor having an excitation conductor attached thereto in a manner opposing the magnetic conductor, the sensor being configured to detect from the receiving conductor change in inductance of the magnetic conductor due to rotation of the excitation conductor as change in a rotation angle of the rotating body. The invention also relates to a method of manufacturing the same, and an intake control system for an engine including the same sensor.
2. Description of the Related Art
Such an inductance-type rotation angle sensor is already known, as disclosed in Japanese Patent Application Laid-open No. 2008-96231.
In such an inductance-type rotation angle sensor, for the purpose of enhancing the detection precision of angle change of the rotating body, it is important that the opposing gap between the magnetic and receiving conductors of the stator and the excitation conductor of the rotating body should be stabilized and narrowed as much as possible. In the glass epoxy resin substrate on which the magnetic and receiving conductors are printed, due to the orientation of glass fibers therein, the coefficient of linear expansion in the plate-surface direction is extremely small, whereas the coefficient of liner expansion in the plate-thickness direction is relatively large. Accordingly, when the inductance-type rotation angle sensor is used in an environment where temperature changes extremely, like in the vicinity of an engine, the opposing gap may change due to change in thickness of the substrate, and the detection precision of angle change of the rotating body may be deteriorated. However, the conventional inductance-type rotation angle sensor is actually lacking in consideration to prevent the thickness of the substrate from changing due to temperature change.